This invention relates generally to the field of internal combustion engines and more specifically to an internal combustion engine of modular construction with a tilt top access and process for making same.
The internal combustion engine has been offered in many shapes and forms for over a hundred years. Design and construction of these engines has for the most part been limited to large heavy bulky castings that offer few weight saving advantages and even fewer options for ease of service or repair. In the prior art, the crankcase and cylinders are all cast in one unit and the cylinder head is normally cast in one unit as well. These engines are utilized in all types of land, sea and aviation applications. An important consideration in each of these applications is the size and weight of the engine. There is normally a trade-off between the structural integrity or durability of an engine and the size and weight of the engine. Engine manufacturers design overly massive engine parts to increase the durability and useful life of an engine. However, utilization of massive engine parts increases the weight and size of the engine and can actually increase engine wear by increasing the dynamic weight of the moving parts. Thus there is a need for an engine that is lighter in weight, more compact in design and also durable. Further, because the prior art uses engine blocks that are cast as single units, the blocks are cast with a single continuous water jacket. The coolant enters the front of the engine and travels through the connected cylinder water jackets in a direction that is parallel to the crankshaft and increasing in temperature as the coolant passes from cylinder to cylinder. The coolant then returns to the front of the engine by way of a single cast cylinder head, again traveling parallel to the crankshaft and further increasing in temperature. This prior art creates a long cooling path that in turn creates hot spots in the engine with the last cylinders to receive coolant operating at higher temperatures than the first cylinders. When cast in one unit, consisting of crankcase, cylinders and water jackets, if there are defects in the casting, the entire casting needs replacement. Replacement of large and heavy castings is very time consuming and costly. When large castings with intricate cores are produced, the possibility of failure is increased. Casting failures drive manufacturing cost up and this translates to higher consumer cost. In the large single casting, heat is transferred from one cylinder to another through thermal conductivity and this leads to additional engine cooling issues. The prior art, with its large and heavy castings, also means higher shipping weights and larger inventory requirements, adding once again to the delivered cost of the final product.
U.S. Pat. No. 6,196,181, which issued to Pong on Mar. 6, 2001, describes an engine which employs a cam follower mechanism to reduce wear and reduce the size of an assembled engine. The cam follower mechanism utilizes guide rails located to reduce side thrust on the valve stem. The engine employs a high speed quill shaft to synchronize independent cam shafts existing in each of a plurality of interconnected engines. The engine is assembled using a single size fastener to provide a uniform stress gradient within the engine. The engines are interconnected utilizing O-ring seals. The engine provides a piston crown utilizing a connecting rod directly connected to the bottom surface of the piston crown. The piston crown is stabilized along the longitudinal cylinder axis by a rail guide. Connecting rods are provided which require less than one hundred eighty degrees (180 degree) circumference of a crankshaft pin for support so that a plurality of connecting rods can be associated with a single crankshaft pin. A tabbed bearing fits under the plurality of connecting rods to provide lubrication between the connecting rods and the crankshaft pin. Connecting rods are held to the crankshaft pin by a circular retaining ring. The engine provides a separate cylinder head and cylinder which is attached via a circular deformable retaining band to form a metal to metal seal. The engine provides an independent lubrication system in each engine. Coolant or lubricant is provided to each engine in parallel so that the temperature of the coolant entering each engine is the same. A large diameter modular crankshaft is provided. The engine is assembled by interconnecting two engine halves around the cylinder barrel to form one engine unit.
U.S. Pat. No. 4,763,619, which issued to Eitel on Aug. 6, 1988, describes a multi-cylinder internal combustion engine of the type having a crankshaft and a block comprised of first and second mating half sections joined in a common plane which passes through and along the axis of the crankshaft. The half sections provide a crankcase crankshaft bearing support and cylinder portions. A unitized cylinder head and sleeve construction is provided. A cooperative securing mechanism is provided for securing the unitized cylinder head and sleeve construction to the engine block. The invention relates to a multi-cylinder internal combustion engine utilizing a split block and crankcase with a unitized cylinder head and liner, and more particularly to such an internal combustion engine utilizing multiple cylinders in which the block is formed in two half sections joined in a common plane which passes through and along the axis of the crankshaft and in which the two half sections comprise a unitized cylinder head and liner.
U.S. Pat. No. 2,491,630, which issued to Voorhies on Dec. 20, 1949, describes an internal combustion engine with a vertically split cylinder construction wherein the entire head, block, and crankcase are formed in two half sections and bolted together.
U.S. Pat. No. 1,408,179, which issued to Paul du Pont on Feb. 28, 1922, describes an internal combustion engine with a casing or housing of a special form and construction which forms a complete enclosure for the engine and by removal of a unitary cover permits convenient access to all the internal parts of the engine.
U.S. Pat. No. 1,622,965, which issued to Napier on Mar. 29, 1927, describes an internal combustion engine with each cylinder comprising a head and a barrel formed as a unit by forging of the head with the barrel.
U.S. Pat. Nos. 1,260,847; 1,145,995 and 900,083, describe an internal combustion engine with separate cylinder heads and barrels, but in that prior art the focus is on the improvement of the water jacket cooling system surrounding the cylinders and improvements thereto.
U.S. Pat. Nos. 904,562; 898,678, describe an internal combustion engine with separate cylinder heads and barrels, but in that prior art the focus is on the reduction of the number of pipes and fittings necessary to cause the cylinder water jacket cooling system to work.
U.S. Pat. Nos. 6,543,405 and 7,146,724 B2 Millerman, describes an internal combustion engine with a method of assembly using a lower block arrangement and a one piece extruded cylinder module comprising all cylinders as a Siamese unit. With this invention, the connecting rods must be installed on the crankshaft before the crankshaft can be installed in the engine. This approach is very difficult and awkward for a single technician to perform, especially during a field repair. The patent also refers to a mid-plate that is passed over all the pistons at the same time. This task is also very difficult for one technician to perform. When the one piece extruded multi-cylinder unit is installed over the pistons, inserting the pistons into the cylinders without damage to the piston rings presents a challenge. This will require several technicians working together or will require very special tools or fixtures as described in the patent. Field repair will be extremely difficult and will certainly result in many engine failures due to poor repairs. The Millerman patent refers to the use of a V style upper cylinder assembly and states that such a V style assembly can be installed on the same lower block design. However, the use of a V style upper assembly is not possible using Millerman's design. In the V application the rotating assembly would strike the sides of the lower block and therefore cannot work. Millerman's design also makes no provision for the replacement of the main journal housings and, if damaged, the entire engine along with the lower block would need to be removed and transported for repair. This repair would require line boring which is a very special machining process and line boring is also required during the original production process.
Almost all the prior art has approached the construction of an internal combustion engine not as a set of small light components, but more as a whole engine with large heavy component parts. As a result, there are numerous deficiencies in the prior art that the present invention overcomes. This unique invention presents an upper and lower block construction with modular cylinders as well as a tilting upper block design in which the major engine parts are interchangeable. Specifically, the lower block of the engine forms the base on which all other parts mount and is capable of receiving either in-line or V style upper block units. The lower block is essentially the same design for all engines within the engine family, only varying in length to accommodate more or less cylinders, as required by the application. Mounted on the upper block is a plurality of single separate modular cylinder jug(s). Each cylinder jug, regardless of the number of cylinders needed for the size engine application, is cast and machined to the same dimensions for the engine family. Mounted on and through the modular cylinder jug is a single separate modular cylinder head. Each head, regardless of the number of cylinders needed for the size engine application, is cast and machined to the same dimensions for the engine family. Mounted on the cylinder head is a single separate modular cylinder head valve cover. Each head valve cover, regardless of the number of cylinders needed for the size engine application, is cast and machined to the same dimensions for the engine family. Within each cylinder jug is located a cylinder sleeve all of which are dimensionally the same for the engine family. The prior art teaches that an engine is cast as two large major parts, a Siamese cylinder block and a single cylinder head covering a complete bank of cylinders. The block and the head are both single large and heavy castings for the number of cylinders required in the application. The numerous deficiencies in the prior art will be enumerated now and the invention's qualities and benefits, that overcome these deficiencies, will be detailed.
In the prior art, if parts of the engine such as the pistons, piston rings, valves, cylinder sleeves, cylinder heads, crankshafts or other parts internal to the engine need repair, due to the large single castings, the entire engine needs to be removed and disassembled for repairs. This is expensive and time consuming. In the present invention, the design construction allows quick and economical repairs to individual cylinders and the entire engine does not need to be disassembled. In order to work on any individual cylinder jug, piston, rings, head or connecting rod, only the cylinder module that needs repair is affected. In the case of the crankshaft, the main bearings can be replaced from the top of the engine and if damaged, the main journal housings are also replaceable. Both bearings and bearing housings can be replaced without the removal of the lower block casting from the application. No repair machining of major castings is ever required and this includes line boring. This saves repair time and cost.
With the prior art, the single Siamese block and head castings are large and heavy. This results in added weight which the engine work is required to overcome. In applications where the engine is used to propel a vehicle, marine vessel or airplane, this results in added cost of operation including greater fuel usage. The present invention using small, modular parts and its ability to use lighter metals, reduces the weight of the engine by as much as one half and thereby reduces the cost of operation. The reduced weight is accomplished by virtue of the fact that lighter metals such as aluminum can be used while still maintaining durability. With the crankshaft cradled into the lower block, the downward force of the combustion event sends this force into the major lower block casting and not onto the caps or cap threads as with the prior art. With the present invention the upper and lower blocks can be die cast without the need for intricate and fragile cores. With the present invention, there are no cast-in water or oil galley channels in either the lower or upper block. This reduces the casting cost as well as the number of casting defects thereby reducing the overall production cost. Less metal waste in manufacture of the engine parts results in engine production savings over the prior art. Further, because in the prior art blocks and heads are large and single cast, there is a requirement for larger manufacturing and machining equipment in order to produce the parts. These larger machines are more expensive and occupy more space on the manufacturing floor. The present invention utilizes smaller manufacturing and machining equipment which is less expensive and takes up less manufacturing floor space. Further, in the prior art, if there is a defect in the manufactured casting of the large block or head or if there is a later failure in the casting, the entire large and heavy casting will need to be scraped and replaced. In the present invention, only the failed modular part, modular cylinder jug, or modular cylinder head, will need to be replaced, with no affect on the other cylinders. By removing the water jackets from the large Siamese engine block casting and incorporating them into the small individual cylinder jugs and cylinder heads, the process is simplified tremendously. With the present invention, casting failures will be rare. An additional benefit is that with no cores required in the upper and lower block casting production, there will be no need to remove or wash out casting cores, which can be a difficult and time consuming process. The elimination of this core removal process will reduce the cost of producing these parts. Another tremendous benefit of this new invention is that when the individual cylinders and heads are replaced, the water jackets are also replaced. The present invention provides little concern for water jacket failure. Thermal cavitation and galvanic corrosion as well as other factors cause many premature water jacket failures but, with the present invention, concern for water jacket failure is virtually eliminated. Due to the difficulty and cost of repair, the prior art uses thick and heavy water jacket walls in order to overcome the problem of premature water jacket failures and to increase the longevity of the castings. This only adds to the engine weight. With the present invention, the ease and inexpensiveness of water jacket replacement, allows the use of thinner and lighter water jacket materials. All of the shortcomings of the prior art ultimately affects the consumer price in a negative way.
In the prior art, engines are cooled by a water jacket cast in the Siamese cylinder block and cylinder head. The coolant path is a single loop of front to back and back to front coolant flow. It enters the engine block at one point in the front and travels through the engine to the rear where it returns to the front of the engine via the one piece cylinder head. As the coolant travels from front to back, it travels in a path that is parallel to the crankshaft and it increases in temperature as it passes each cylinder, resulting in the cylinders last to receive coolant operating at higher temperatures. The coolant returns to the front of the engine through the cylinder head and also travels in a path that is parallel to the crankshaft. Once again the coolant increases in temperature as the coolant passes each cylinder in line. This results in operating inefficiency and in accelerated engine wear in the hotter cylinders. In the present invention, the chilled coolant is delivered to each cylinder individually via a common water manifold. The coolant is delivered to the bottom of each separate individual cylinder jug and enters into the cylinder jug water jacket surrounding the cylinder sleeve. The coolant travels through the cylinder jug in a path that is perpendicular to the crankshaft. After circulating around the individual cylinder jug and sleeve, the coolant exits the cylinder jug into the individual cylinder head where the coolant travels in a perpendicular path to the cylinder jug coolant flow and perpendicular to the crankshaft. After cooling and crossing through the cylinder head, the coolant exits into the wet exhaust manifold. The coolant then returns to the heat exchange device to be cooled for recirculation. In the present invention application, each individual cylinder is supplied with coolant that is uniformly cold in temperature and the coolant path through each cylinder is the same length, thereby creating a more effective and uniform cooling process. Cooling paths through the individual cylinders is only a matter of a few inches and not a matter of feet, as is with the prior art. The cooling paths are parallel to each other yet perpendicular to the crankshaft. Shorter cooling paths means a greater volume of cold coolant comes in contact with each cylinder. There is no through engine coolant warm up (coolant temperature stacking), causing some cylinders to operate hotter than the other cylinders. Unlike the prior art, the inventive engine operates more efficiently and with less wear, thereby reducing the need for repairs and reducing operating cost when compared to the prior art. Further, in the present invention, additional cooling is provided by an air gap between each individual cylinder jug and head assembly unit and the next in-line cylinder jug and head assembly unit, mounted on a multi-cylinder engine. The air gap allows air to circulate around the individual cylinder units to provide additional cooling. Further, since the units are not attached metal to metal, as is the case in the Siamese cylinder cast cylinder block of the prior art, there is no thermal heat transfer from one cylinder to the next. The prior art creates excessive thermal conductivity throughout the entire Siamese single cast cylinder block and cylinder head. With the new art, the use of lighter metals such as aluminum for cylinder jugs and cylinder heads, is possible. The lower block can also be cast in aluminum or other lightweight metals since the crankshaft is cradled in the lower block and not suspended on caps and cap threads. The upper block can also be cast in light metals since the underside is easily accessible for machining and all critical threads can be steel lined easily with reverse mounted inserts. Aluminum can be used in areas such as water jackets that will allow for faster heat transfer and therefore provide improved cooling. In the prior art, the horizontal and parallel flow of the coolant through the water jackets can be restricted by casting requirements such as push rod passages and other obstructions that reduce the efficiency of the coolant flow. In the present invention the perpendicular to the crankshaft flow of the coolant through the cylinder jug(s) eliminates obstruction concerns. The current invention also provides for a coolant flow through the cylinder head that is perpendicular to the coolant flow in the cylinder jug(s) and also perpendicular to the crankshaft.
This current invention allows the use of a conventional camshaft (driven by steel gears) and flat tappet or roller lifters. It uses a standard pushrod design, the durability of which has been proven for more than one hundred years. In the prior art, due to the lack of interchangeability of parts, dealers and parts suppliers are required to maintain large parts inventories in order to supply the needs of their customers. In the present invention, the interchangeability of the parts within a large engine family is over ninety percent so parts inventories can be reduced considerably. With the present invention, large parts inventories are no longer required due to front and rear part interchangeability as well as cylinder modules and head modules being interchangeable within the engine family. This reduces inventory carrying cost as well as repair costs. With the present invention an engine family can be created that all use the same displacement per cylinder. A 2, 3, 4, 5, 6, 8 and 10 cylinder in-line engine family can be constructed that all use the same parts. The family can be extended to include a V 4, 6, 8, 10, 12, 16 and 20 cylinder engines that use the same parts as well. The lower block for the in-line 6 is the same lower block for the V 12. The in-line engine front and rear assemblies are all the same and are interchangeable and the V front and rear assemblies interchange with all V engines within the engine family. Finally, in the present invention a single individual cylinder module can be easily replaced without disassembly of other parts of the engine. Using a tapered mating design where the cylinder head mates with the intake and exhaust manifold, the removal and replacement of a single cylinder module, consisting of a valve cover, cylinder head, cylinder jug, piston, connecting rod and rod bearing, is easily accomplished from the top of the engine, without the removal or loosening of other parts. The connecting rod bolts are installed and removed from the top of the engine and their splayed insertion application eliminates tool interference. The process of removing and replacing a single complete cylinder can be easily accomplished by a single technician within a few minutes.